CAREER: Single-Atom Alloy Catalyst Design for the Electrocatalytic Reduction of Nitrate to Ammonia: Linking Electronic Structure to Geometry and Catalytic Performance

硝酸盐 (NO3−) 是世界上最普遍的地下水污染物之一，对人类和生态系统健康构成严重威胁。因此，迫切需要管理工业、食品和水系统中的硝酸盐废物。电催化硝酸盐还原反应（NO3RR）是将硝酸盐转化为有价值的氨（NH3）的一种有前景的方法；然而，围绕 NO3RR 的关键科学问题和挑战限制了其实际应用。拟议的研究重点是通过计算解决多个科学问题，以更好地理解单原子合金催化剂上的 NO3RR 与氨的关系。该项目与密歇根大学自然历史博物馆和沃什特诺社区学院合作，将研究与教育推广计划结合起来，以促进 STEM 教育和催化培训。拟议的研究重点是实现两个科学目标，以增强 NO3RR 转化为氨的能力。先前的结果表明，过渡金属电催化剂的最大 NO3RR 活性和选择性受到吸附物之间的线性能量比例关系 (LSR) 的阻碍。第一个科学目标旨在通过单原子合金（SAA）电催化剂回答NO3RR的机理问题，以打破这些LSR。 SAA 是一类很有前途的催化剂，其中金属主体的表面层中存在少量孤立的金属原子。然而，SAA 几乎没有被探索用于 NO3RR。使用最先进的大正则密度泛函理论，我们将测试以下假设：1) 明智选择的 SAA 将打破限制纯金属上 NO3RR 活性的 LSR，2) 淬灭 N-N 耦合以有利于 NH3 选择性。 第二个科学目标旨在阐明 SAA 的几何形状和电子结构如何与 NO3RR 活性和选择性联系起来。这些见解将有助于设计 SAA 催化剂，以分解 NO3RR 的 LSR。这项研究的预期成果是对 SAA 及其打破 NO3RR LSR 的能力的新机制理解、将其性质与反应性联系起来的 SAA 设计规则，以及对溶剂和在 NO3RR 上应用的电化学势的作用的一般见解。拟议的教育活动是： (i) 创建一个“研究站”博物馆展览，向公众传授催化和硝酸盐问题的知识； (ii) 通过暑期科学研究计划吸引中学生参与； (iii) 通过科学传播研究员计划教授和实践科学传播； (iv) 担任第一代社区学院学生的夏季研究导师。拟议的综合研究和教育活动将支持多学科研究培训，增强 STEM 公平性、多样性和包容性，并提高美国经济竞争力。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nitrate (NO3−) is among the most ubiquitous groundwater pollutants in the world and a serious threat to human and ecosystem health. Thus, there is a compelling need to manage nitrate waste across industry, food, and water systems. The electrocatalytic nitrate reduction reaction (NO3RR) is a promising approach to convert nitrate into valuable ammonia (NH3); however, critical scientific questions and challenges surrounding NO3RR limit its practical use. The proposed research focuses on computationally addressing multiple scientific questions to better understand NO3RR to ammonia on single atom alloy catalysts. This project integrates the research with an educational outreach plan in collaboration with the Museum of Natural History at the University of Michigan and the Washtenaw Community College to promote STEM education and catalysis training.The proposed research focuses on addressing two scientific objectives to enhance NO3RR to ammonia. Prior results showed that the maximum NO3RR activity and selectivity on transition metal electrocatalysts is hindered by linear energy scaling relations (LSRs) between adsorbates. The 1st scientific objective aims to answer mechanistic questions of NO3RR by single-atom alloy (SAAs) electrocatalysts, with the goal to break these LSRs. SAAs are a promising class of catalysts in which small amounts of isolated metal atoms are present in the surface layer of a metal host. Yet SAAs have hardly been explored for NO3RR. Using state-of-the-art Grand Canonical Density Functional Theory, we will test the hypotheses that 1) judiciously selected SAAs will break LSRs that limit NO3RR activity on pure metals, and 2) quench N-N coupling to favor NH3 selectivity. The second scientific objective aims to elucidate how geometry and electronic structure of SAAs link to NO3RR activity and selectivity. These insights will help design SAA catalysts that break LSRs for NO3RR. The expected outcomes of this research are new mechanistic understanding of SAAs and their ability to break LSRs for NO3RR, design rules for SAAs that link their properties to reactivity, and general insights into the role of solvent and applied electrochemical potential on NO3RR. The proposed educational activities are: (i) Creating a “Research Station” museum exhibit that will teach the public about catalysis and the nitrate problem; (ii) Engaging middle school students through a summer science research program; (iii) Teaching and practicing science communication through a Science Communication Fellows Program; and (iv) Serving as summer research mentors to first-generation Community College students. The proposed integrated research and educational activities will support multidisciplinary research training, enhance STEM equity, diversity and inclusion, and increase USA economic competitiveness.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.